High-pressure measurements of the resistivity of americium metal are reported to 27 GPa and down to temperatures of 0.4 K. The unusual dependence of the superconducting temperature (Tc) on pressure is deduced. The critical field [HC(0)] extrapolated to T = 0] increases dramatically from 0.05 to ∼1 T as the pressure is increased, suggesting that the type of superconductivity is changing as pressure increases. At pressures of ∼16 GPa the 5f electrons of Am are changing from localized to itinerant, and the crystal structure also transforms to a complex one. The role of a Mott-type transition in the development of the peak in Tc above 16 GPa is postulated.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)